Error99 after canon 20d firmware upgrade?

I am a professional photographer. From last two months I am using the Canon 20 d. Some time I face the same problem that you are facing right now at the time of the firm ware upgrade. The Canon Error 99 is the error message that pops up when there is a contact issue between the lens and the body of a camera. Also it represents the defective storage card, bad battery, and anything else the software doesn't seem to like. It is basically the catch all error messages little bit like the familiar windows BSOD. You can easily get rid of this error. For that plug out the battery of Canon for the several minutes. If still error has not removed than repeat the process for the several time. Hope by the end of this your problem will solve completely. It was really nice to help you on this.